zfs/sys/dnode.h

	dnode.h revision ea8dc4b6d2251b437950c0056bc626b311c73c27
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _SYS_DNODE_H
#define _SYS_DNODE_H

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/zfs_context.h>
#include <sys/avl.h>
#include <sys/spa.h>
#include <sys/txg.h>
#include <sys/refcount.h>
#include <sys/dmu_zfetch.h>

#ifdef  __cplusplus
extern "C" {
#endif

/*
 * Flags.
 */
#define DNODE_MUST_BE_ALLOCATED 1
#define DNODE_MUST_BE_FREE  2

/*
 * Fixed constants.
 */
#define DNODE_SHIFT     9   /* 512 bytes */
#define DN_MIN_INDBLKSHIFT  10  /* 1k */
#define DN_MAX_INDBLKSHIFT  14  /* 16k */
#define DNODE_BLOCK_SHIFT   14  /* 16k */
#define DNODE_CORE_SIZE     64  /* 64 bytes for dnode sans blkptrs */
#define DN_MAX_OBJECT_SHIFT 48  /* 256 trillion (zfs_fid_t limit) */
#define DN_MAX_OFFSET_SHIFT 64  /* 2^64 bytes in a dnode */

/*
 * Derived constants.
 */
#define DNODE_SIZE  (1 << DNODE_SHIFT)
#define DN_MAX_NBLKPTR  ((DNODE_SIZE - DNODE_CORE_SIZE) >> SPA_BLKPTRSHIFT)
#define DN_MAX_BONUSLEN (DNODE_SIZE - DNODE_CORE_SIZE - (1 << SPA_BLKPTRSHIFT))
#define DN_MAX_OBJECT   (1ULL << DN_MAX_OBJECT_SHIFT)

#define DNODES_PER_BLOCK_SHIFT  (DNODE_BLOCK_SHIFT - DNODE_SHIFT)
#define DNODES_PER_BLOCK    (1ULL << DNODES_PER_BLOCK_SHIFT)
#define DNODES_PER_LEVEL_SHIFT  (DN_MAX_INDBLKSHIFT - SPA_BLKPTRSHIFT)

/* The +2 here is a cheesy way to round up */
#define DN_MAX_LEVELS   (2 + ((DN_MAX_OFFSET_SHIFT - SPA_MINBLOCKSHIFT) / \
    (DN_MIN_INDBLKSHIFT - SPA_BLKPTRSHIFT)))

#define DN_BONUS(dnp)   ((void*)((dnp)->dn_bonus + \
    (((dnp)->dn_nblkptr - 1) * sizeof (blkptr_t))))

#define EPB(blkshift, typeshift)    (1 << (blkshift - typeshift))

struct dmu_buf_impl;
struct objset_impl;
struct zio;

enum dnode_dirtycontext {
    DN_UNDIRTIED,
    DN_DIRTY_OPEN,
    DN_DIRTY_SYNC
};

typedef struct dnode_phys {
    uint8_t dn_type;        /* dmu_object_type_t */
    uint8_t dn_indblkshift;     /* ln2(indirect block size) */
    uint8_t dn_nlevels;     /* 1=dn_blkptr->data blocks */
    uint8_t dn_nblkptr;     /* length of dn_blkptr */
    uint8_t dn_bonustype;       /* type of data in bonus buffer */
    uint8_t dn_checksum;        /* ZIO_CHECKSUM type */
    uint8_t dn_compress;        /* ZIO_COMPRESS type */
    uint8_t dn_pad1[1];
    uint16_t dn_datablkszsec;   /* data block size in 512b sectors */
    uint16_t dn_bonuslen;       /* length of dn_bonus */
    uint8_t dn_pad2[4];

    /* accounting is protected by dn_dirty_mtx */
    uint64_t dn_maxblkid;       /* largest allocated block ID */
    uint64_t dn_secphys;        /* 512b sectors of disk space used */

    uint64_t dn_pad3[4];

    blkptr_t dn_blkptr[1];
    uint8_t dn_bonus[DN_MAX_BONUSLEN];
} dnode_phys_t;

typedef struct dnode {
    /*
     * lock ordering:
     *
     * db_mtx > dn_dirty_mtx
     *  dbuf_syncdone
     *
     * dn_struct_rwlock/r > dn_dirty_mtx
     *  dmu_object_info
     *
     * dn_struct_rwlock/r > db_mtx > dn_dirty_mtx
     *  dbuf_dirty
     *  dbuf_setdirty
     *
     * dn_struct_rwlock/w > db_mtx > dn_mtx
     *  dnode_increase_indirection -> dbuf_find
     *  dbuf_hold_impl
     *  dnode_set_bonus
     *
     * dn_struct_rwlock/w > dn_mtx
     *  dnode_increase_indirection
     *
     * dn_dirty_mtx > dn_mtx
     *  dnode_buf_pageout
     *
     * db_mtx > dn_mtx
     *  dbuf_create
     */

    /*
     * dn_struct_rwlock protects the structure of the dnode.
     * In particular, it protects the number of levels of indirection.
     */
    krwlock_t dn_struct_rwlock;

    /*
     * Our link on dataset's dd_dnodes list.
     * Protected by dd_accounting_mtx.
     */
    list_node_t dn_link;

    /* immutable: */
    struct objset_impl *dn_objset;
    uint64_t dn_object;
    struct dmu_buf_impl *dn_dbuf;
    dnode_phys_t *dn_phys; /* pointer into dn->dn_dbuf->db.db_data */

    /*
     * Copies of stuff in dn_phys.  They're valid here even before
     * the dnode is first synced.
     */
    dmu_object_type_t dn_type;  /* object type (immutable) */
    uint8_t dn_bonustype;       /* bonus type (immutable) */
    uint16_t dn_bonuslen;       /* bonus length (immutable) */
    uint8_t dn_nblkptr;     /* number of blkptrs (immutable) */
    uint8_t dn_datablkshift;    /* zero if blksz not power of 2! */
    uint32_t dn_datablksz;      /* in bytes */
    uint16_t dn_datablkszsec;   /* in 512b sectors */

    uint8_t dn_checksum;        /* ZIO_CHECKSUM type */
    uint8_t dn_compress;        /* ZIO_COMPRESS type */

    /*
     * The following are kept up-to-date in the *open* context, the syncing
     * context should only pay attention to the dn_next_* values.
     */
    uint8_t dn_nlevels;
    uint8_t dn_indblkshift;

    uint8_t dn_next_nlevels[TXG_SIZE];
    uint8_t dn_next_indblkshift[TXG_SIZE];

    /* protected by os_lock: */
    uint32_t dn_dirtyblksz[TXG_SIZE];   /* dirty block size in bytes */
    list_node_t dn_dirty_link[TXG_SIZE];    /* next on dataset's dirty */

    /* protected by dn_mtx: */
    kmutex_t dn_mtx;
    list_t dn_dirty_dbufs[TXG_SIZE];
    uint64_t dn_maxblkid;
    avl_tree_t dn_ranges[TXG_SIZE];
    uint64_t dn_allocated_txg;
    uint64_t dn_free_txg;
    uint64_t dn_assigned_txg;
    struct dmu_tx *dn_assigned_tx;      /* if only one tx cares */
    kcondvar_t dn_notxholds;
    enum dnode_dirtycontext dn_dirtyctx;
    uint8_t *dn_dirtyctx_firstset;      /* dbg: contents meaningless */

    /* protected by own devices */
    refcount_t dn_tx_holds;
    refcount_t dn_holds;

    kmutex_t dn_dbufs_mtx;
    list_t dn_dbufs;        /* linked list of descendent dbuf_t's */
    struct dmu_buf_impl *dn_bonus;  /* bonus buffer dbuf */

    /* holds prefetch structure */
    struct zfetch   dn_zfetch;
} dnode_t;

typedef struct free_range {
    avl_node_t fr_node;
    uint64_t fr_blkid;
    uint64_t fr_nblks;
} free_range_t;

dnode_t *dnode_special_open(struct objset_impl *dd, dnode_phys_t *dnp,
    uint64_t object);
void dnode_special_close(dnode_t *dn);

int dnode_hold(struct objset_impl *dd, uint64_t object,
    void *ref, dnode_t **dnp);
int dnode_hold_impl(struct objset_impl *dd, uint64_t object, int flag,
    void *ref, dnode_t **dnp);
void dnode_add_ref(dnode_t *dn, void *ref);
void dnode_rele(dnode_t *dn, void *ref);
void dnode_setdirty(dnode_t *dn, dmu_tx_t *tx);
int dnode_sync(dnode_t *dn, int level, struct zio *zio, dmu_tx_t *tx);
void dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
    dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
void dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
    dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
void dnode_free(dnode_t *dn, dmu_tx_t *tx);
void dnode_byteswap(dnode_phys_t *dnp);
void dnode_buf_byteswap(void *buf, size_t size);
void dnode_verify(dnode_t *dn);
int dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx);
uint64_t dnode_current_max_length(dnode_t *dn);
uint64_t dnode_max_nonzero_offset(dnode_t *dn);
void dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx);
void dnode_clear_range(dnode_t *dn, uint64_t blkid,
    uint64_t nblks, dmu_tx_t *tx);
void dnode_diduse_space(dnode_t *dn, int64_t space);
void dnode_willuse_space(dnode_t *dn, int64_t space, dmu_tx_t *tx);
void dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx);
uint64_t dnode_block_freed(dnode_t *dn, uint64_t blkid);
void dnode_init(void);
void dnode_fini(void);
int dnode_next_offset(dnode_t *dn, boolean_t hole, uint64_t *off, int minlvl,
    uint64_t blkfill);
void dnode_evict_dbufs(dnode_t *dn);

#ifdef ZFS_DEBUG

/*
 * There should be a ## between the string literal and fmt, to make it
 * clear that we're joining two strings together, but that piece of shit
 * gcc doesn't support that preprocessor token.
 */
#define dprintf_dnode(dn, fmt, ...) do { \
    if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
    char __db_buf[32]; \
    uint64_t __db_obj = (dn)->dn_object; \
    if (__db_obj == DMU_META_DNODE_OBJECT) \
        (void) strcpy(__db_buf, "mdn"); \
    else \
        (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
            (u_longlong_t)__db_obj);\
    dprintf_ds((dn)->dn_objset->os_dsl_dataset, "obj=%s " fmt, \
        __db_buf, __VA_ARGS__); \
    } \
_NOTE(CONSTCOND) } while (0)

#define DNODE_VERIFY(dn)        dnode_verify(dn)
#define FREE_VERIFY(db, start, end, tx) free_verify(db, start, end, tx)

#else

#define dprintf_dnode(db, fmt, ...)
#define DNODE_VERIFY(dn)
#define FREE_VERIFY(db, start, end, tx)

#endif

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_DNODE_H */